Preface viii Preface ing of this book, Mitas Ongtengco has played a major role -supervising the subjects, administering the budget, and cheerfully typing and retyping the manuscript.We are indebted to Michael Halliday and Ruquiya Hasan for their insights into the nature of text and its relation to context and lexicogrammar, which will be evident from our many references to their work. Our debt to H. A. Gleason, Jr., is less obvious, since relevant parts of his thinking remain unpublished. We gladly acknowledge his many hours of helpful discussion. It was, in fact, through one of Gleason's students, Waldemar Gutwinski, that we first became interested in cohesion and its application to szhizophrenic discourse.Finally, we are most grateful to the many subjects who participated in these studies and who so kindly allowed us to examine their talk. The fees they were paid could not possibly compensate them for the time and goodwill they brought to their task.